1. Field
The present application generally relates to improving electric grid stabilization by utilizing an electric vehicle (EV) battery to store excess electric grid capacity. A method and a system for storing excess electric grid capacity are disclosed.
2. Description of the Background
When the charging of an electric vehicle (EV) is initiated and a State of Charge (SOC) is greater than a minimum SOC, the charging of the EV is halted. FIG. 1 illustrates typical prior art behavior of a State of Charge (SOC) of an electric vehicle (EV) when being charged. In the prior art, a high EV minimum SOC 102 of 95% is set close to a maximum SOC 104 of 100% in a Vehicle-to-Grid (V2G) mode. With the high EV minimum SOC 102, an operational window 112 for storing a charge is very narrow or only 5% of charge capacity. When the grid requests that the EV store electric energy, the EV's SOC reaches or exceeds the maximum SOC quickly. When the SOC in the EV reaches or exceeds the maximum SOC, the EV charging is halted and the EV may not be utilized to store electrical energy on behalf of the electrical grid or utility. In other words, when the V2G maintains the EV at a high minimum SOC 102, the SOC easily hits a peak SOC 104 (for example, 100%). Moreover, in order to maintain the EV's SOC above the minimum SOC, the high minimum SOC and the narrow operational window 112 require the EV to recharge frequently. As such, the EV's opportunities to take advantage of a more optimal time to charge to the maximum SOC 104 are reduced.